class Solution {
public:
    bool isMatch(string s, string p) {
        int m = s.size();
        int n = p.size();
        s = " "+s;
        p = " "+p;
        vector<vector<bool>> dp(m+1,vector<bool>(n+1));
        dp[0][0] = true;//两个空串能够匹配
        for(int i=1;i<=n;i++)
        {
            if(p[i]=='*')
                dp[0][i] = true;//前导为"*"，可以匹配
            else
                break; 
        }
        for(int i =1;i<=m;i++)
        {
            for(int j=1;j<=n;j++)
            {
               if(p[j]=='*')
               {
                   dp[i][j] = dp[i-1][j]||dp[i][j-1];
               }
               else
               {
                   if(p[j]=='?'||p[j]==s[i])
                        dp[i][j] = dp[i-1][j-1];
               }
            }
        }
        return dp[m][n]; 
    }
};